This tool only derives 20 address_index per script type and will only derive 20 more addresses from the last used one.
With that, it will not work since he needs his key/address from around 50,000 address_index, it will only work in that specific case if the lower index with a gap of 20 addresses are all used.
Other tools may have higher gap limit but I'm pretty sure that nothing will set it to more than 50,000 by default.
So it has to be derived from a specific range like the example in my previous reply.
The problem here is he didn't shared the code of that "script" that he mentioned.
Because it could be (un)intentionally using a different derivation path that Electrum uses.
You're right, it only check the 20 addresses I tested out.
I think the
xpub-scanner from Ledger HQ can scan these 50k addresses; the only disadvantage it doesn't support zPub master public key. However, the tool support segwit and native segwit to be able to use this scanner he needs to convert it using the "
Bitcoin Extended Public Key Converter" from zPub to xPub to use it in the xPub scanner.
I tried this tool a few months ago with a free API with a limit of 1 million credits from Cryptoapis. You just need to downgrade the default API version from the newer to the oldest one because the new APIs from Cryptoapis do not work on this tool but the old one works.